The Pentagon Planned to Turn Grenade Launchers Into Nonlethal Air Cannons

Converted weapons would knock people over — or douse them in irritating chemicals by JOSEPH TREVITHICK Confronted with an angry mob outside a military base overseas,...

Converted weapons would knock people over — or douse them in irritating chemicals

by JOSEPH TREVITHICK

Confronted with an angry mob outside a military base overseas, American troops set up a specially-modified automatic grenade launcher.

Suddenly protest leaders come under assault by high-speed pulses of air. The barely-visible puffs knock some people over while leaving onlookers and other bystanders untouched.

The bursts soak others in nauseating and irritating chemicals. With the most agitated members subdued, the group scatters.

This is how the U.S. Army Research Laboratory, back in 1998, described the effects of its planned “vortex-ring generator.” The Army had begun developing this, um, novel crowd-control weapon a year earlier in 1997, initially in collaboration with the Marine Corps.

“The concept of crowd control using a vortex-ring generator … is designed to target individuals, persuade them to vacate the area, and promote a divorce from the main body [of the crowd] without reprisals on the gun crew,” researchers George Lucey and Louis Jasper wrote in the 1998 report.

But despite years of work, the weapon — and indeed its whole underlying concept — failed to live up to expectations.

By the 1990s, the science behind vortex rings was hardly new. Scientists had studied the effect both mathematically and physically since the 19th century.

Anyone who has seen a person blow a circle of smoke has seen a vortex ring. The concept is so mundane that companies make simple vortex-ring guns as children’s toys.

Between 1953 and 1956, both the Army and the Navy studied the rings as a means of spreading tear-gas particles or, in much greater intensity, destroying military targets. Both services revived the concept again nearly two decades later.

None of these projects produced a viable weapon. But with the Cold War’s end, the Pentagon imagined its future meant peacekeeping and humanitarian missions. Vortex-ring weapons enjoyed their second resurgence — strictly nonlethal this time.

Above and at top — troops train with standard Mk. 19 grenade launchers. U.S. Army photos

Between 1990 and 1998, American troops found themselves dealing with hostile crowds in countries such as Bosnia and Herzegovina, Haiti and Somalia. Largely equipped to handle traditional enemies, U.S. forces often lacked good options for dealing with angry civilians.

“In the past, the entire crowd would be attacked with tear gas, clubs, dogs or horses, and the result was often a larger crowd recongregating somewhere else,” Lucey and Jasper wrote in their 1998 report to the Army. “The modern approach uses stand-off techniques such as rubber bullets applied to individual leaders, but this is not always nonlethal and tends to incite the rioters.”

On top of that, U.S. troops often had to contend with armed criminal gangs and militants while keeping trying to keep the peace or helping out after a natural disaster. The Pentagon wanted a weapon that would be useful in both a riot and an actual firefight.

A weapon like … the vortex-ring generator.

Revisiting older research, Army weaponeers quickly dismissed the idea of building a new, overly-complex weapon. Instead, the engineers conceived of a kit that could quickly transform a Mk.19 automatic grenade launcher into a nonlethal crowd-control cannon.

The proposed modification would consist of only two components — a tube that slide into the barrel and a belt of special blank rounds. Troops would be able to install the device on their launchers as necessary and without a lot of hassle.

U.S. Army engineers test their prototype vortex ring gun. Army capture

Together with the blank rounds, the new nozzle would create supersonic vortexes and a blinding flash. In addition, soldiers could fill up a reservoir with foul-smelling liquid or the powder that, once burned, makes tear gas.

“The reasoning is that application of a malodor such as cortyl mercapton (skunk perfume) to a specific individual will cause the crowd to voluntarily pull away from that individual,” Lucey and Jasper explained. “And, if an individual is subjected to a chain of impulses that cause physiological discomfort, the individual will vacate the area.”

“The net result is a break in leadership and communication without reprisals (few people have been known to return for revenge on a skunk).”

As with many riot-control weapons, from the very beginning the Army engineers had concerns about generating consistent, repeatable and reliable outcomes. No sane military commander wants to accidentally kill a civilian with a supposedly nonlethal weapon.

Regardless of whether the basic weapon worked or not, Lucey and Jasper sought guidance from the “nonlethal medical community.” Those professionals would have to figure out the safety parameters for the new weapon.

There wasn’t any clear indication that the vortex cannon would work as a crowd-control device. Mathematical models and tests both showed that the rings spread out or broke up quickly — just like when a person blows a smoke ring.

Not only might the blasts not reach their intended targets, they could also drift off course and hit the wrong targets.

Three years after launching the project, engineers finally managed to build a vortex-generator for testing. Instead of a small blank round, this air gun needed gunpowder, C4 or some other explosive to create the desired rings.

Engineers could only fire five shots every hour, according to a separate Army report. The weaponeers would never have been able to directly adapt the design to the Mk. 19 grenade launcher.

The Army Research Laboratory had hoped to turn over, by 2000, the prototype and test results to other engineers who would then build production versions of the weapon. But that never happened.

The Army canceled the project and the Pentagon moved on to other, more promising technologies. The most notable of these projects was the Active Denial System — a microwave “pain beam.”

In concept, engineers expected this futuristic weapon to do many of the same things as the proposed vortex-ring gun. In practice, it suffered from many of the same flaws.

In 2010, the Pentagon sent an Active Denial System to Afghanistan, where it sat for for at least a month without troops ever using it. While engineers continue to tinker with the weapon, so far it hasn’t proved to be any more useful than the vortex-ring gun — which remains largely a novelty.